package com.itheima.service.impl;

import com.alibaba.fastjson.JSON;
import com.alibaba.nacos.common.utils.IoUtils;
import com.hmall.common.dto.Item;
import com.hmall.common.dto.PageDTO;
import com.hmall.feignconfig.itemClient;
import com.itheima.dto.ItemDoc;
import com.itheima.dto.search;
import com.itheima.service.SearchService;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.query.functionscore.FunctionScoreQueryBuilder;
import org.elasticsearch.index.query.functionscore.ScoreFunctionBuilders;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.aggregations.Aggregations;
import org.elasticsearch.search.aggregations.bucket.terms.Terms;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightField;
import org.elasticsearch.search.suggest.Suggest;
import org.elasticsearch.search.suggest.SuggestBuilder;
import org.elasticsearch.search.suggest.SuggestBuilders;
import org.elasticsearch.search.suggest.completion.CompletionSuggestion;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.util.CollectionUtils;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@Service
public class SearchServiceImpl implements SearchService {


    @Autowired
    private RestHighLevelClient client;

    @Autowired
    private com.hmall.feignconfig.itemClient itemClient;

    @Override
    public PageDTO<ItemDoc> list(search search) {


        try {
            SearchRequest request = new SearchRequest("mall");

            buildBasicQuery(search,request);
            request.source().highlighter(
                    new HighlightBuilder().field("name").requireFieldMatch(false)
            );

            // 2.2.分页
            int page = search.getPage();
            int size = search.getSize();
            request.source().from((page - 1) * size).size(size);

            SearchResponse response = client.search(request, RequestOptions.DEFAULT);


            return handleResponse(response);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }

    }

    /**
     * 自动补全
     * @param prefix
     * @return
     */
    @Override
    public List<String> suggestion(String prefix) {

        try{
        SearchRequest request = new SearchRequest("mall");

        request.source().suggest(new SuggestBuilder().addSuggestion(
                "suggestions",
                SuggestBuilders.completionSuggestion("suggestion")
                        .prefix(prefix)
                        .skipDuplicates(true)
                        .size(10)
        ));

        SearchResponse response = client.search(request, RequestOptions.DEFAULT);

        Suggest suggest = response.getSuggest();
        // 4.1.根据补全查询名称，获取补全结果
        CompletionSuggestion suggestions = suggest.getSuggestion("suggestions");
        // 4.2.获取options
        List<CompletionSuggestion.Entry.Option> options = suggestions.getOptions();
        // 4.3.遍历
        List<String> list = new ArrayList<>(options.size());
        for (CompletionSuggestion.Entry.Option option : options) {
            String text = option.getText().toString();
            list.add(text);
        }
        return list;
    } catch (IOException e) {
        throw new RuntimeException(e);
    }

    }

    /**
     * 分组
     * @param search
     * @return
     */
    @Override
    public Map<String, List<String>> filters(search search) {

        try {
            SearchRequest request = new SearchRequest("mall");
            // 2.准备DSL
            // 2.1.query
            buildBasicQuery(search, request);
            // 2.2.设置size
            request.source().size(0);
            // 2.3.聚合
            buildAggregation(request);
            // 3.发出请求
            SearchResponse response = client.search(request, RequestOptions.DEFAULT);
            // 4.解析结果
            Map<String, List<String>> result = new HashMap<>();
            Aggregations aggregations = response.getAggregations();
            // 4.1.根据品牌名称，获取品牌结果
            List<String> category = getAggByName(aggregations, "category");
            result.put("category", category);
            // 4.2.根据品牌名称，获取品牌结果
            List<String> brand = getAggByName(aggregations, "brand");
            result.put("brand", brand);
            return result;

        }catch (IOException e){
            throw new RuntimeException(e);
        }
    }

    // 设置聚合
    private void buildAggregation(SearchRequest request) {
        request.source().aggregation(AggregationBuilders
                                    .terms("category")
                                    .field("category")
                                    .size(100)
                                    );

        request.source().aggregation(AggregationBuilders
                                    .terms("brand")
                                    .field("brand")
                                    .size(100)
                                    );
    }


    private List<String> getAggByName(Aggregations aggregations, String aggName) {
        // 4.1.根据聚合名称获取聚合结果
        Terms brandTerms = aggregations.get(aggName);
        // 4.2.获取buckets
        List<? extends Terms.Bucket> buckets = brandTerms.getBuckets();
        // 4.3.遍历
        List<String> brandList = new ArrayList<>();
        for (Terms.Bucket bucket : buckets) {
            // 4.4.获取key
            String key = bucket.getKeyAsString();
            brandList.add(key);
        }
        return brandList;
    }


    //条件查询
    private void buildBasicQuery(search search,SearchRequest request) {

        // 1.构建BooleanQuery
        BoolQueryBuilder boolQuery = QueryBuilders.boolQuery();

        // 2.关键字搜索
        String key = search.getKey();
        if (key == null || "".equals(key)) {
            boolQuery.must(QueryBuilders.matchAllQuery());
        } else {
            boolQuery.must(QueryBuilders.matchQuery("all", key));
        }
        // 3.分类条件
        if (search.getCategory() != null && !search.getCategory().equals("")){
            boolQuery.filter(QueryBuilders.termQuery("category",search.getCategory()));
        }
        // 品牌
        if (search.getBrand() != null && !search.getBrand().equals("")){
            boolQuery.filter(QueryBuilders.termQuery("brand",search.getBrand()));
        }
        // 价格
        if (search.getMinPrice() != null && search.getMaxPrice() != null ){
            boolQuery.filter(QueryBuilders
                            .rangeQuery("price")
                            .gte(search.getMinPrice())
                            .lte(search.getMaxPrice())
            );
        }


        // 2.算分控制
        FunctionScoreQueryBuilder functionScoreQuery =
                QueryBuilders.functionScoreQuery(
                        // 原始查询，相关性算分的查询
                        boolQuery,
                        // function score的数组
                        new FunctionScoreQueryBuilder.FilterFunctionBuilder[]{
                                // 其中的一个function score 元素
                                new FunctionScoreQueryBuilder.FilterFunctionBuilder(
                                        // 过滤条件
                                        QueryBuilders.termQuery("isAD", true),
                                        // 算分函数
                                        ScoreFunctionBuilders.weightFactorFunction(10)
                                )
                        });
        request.source().query(boolQuery);
    }



    // 结果解析
    private PageDTO<ItemDoc> handleResponse(SearchResponse response) {

        // 4.解析响应
        SearchHits searchHits = response.getHits();

        // 4.1.获取总条数
        long total = searchHits.getTotalHits().value;
        // 4.2.文档数组
        SearchHit[] hits = searchHits.getHits();
        // 4.3.遍历
        List<ItemDoc> hotels = new ArrayList<>();
        for (SearchHit hit : hits) {
            // 获取文档source
            String json = hit.getSourceAsString();
            // 反序列化
            ItemDoc hotelDoc = JSON.parseObject(json, ItemDoc.class);
            hotelDoc.setPrice(hotelDoc.getPrice()*100);

            Map<String, HighlightField> highlightFields = hit.getHighlightFields();
            if (!CollectionUtils.isEmpty(highlightFields)) {
                // 根据字段名获取高亮结果
                HighlightField highlightField = highlightFields.get("name");
                if (highlightField != null) {
                    // 获取高亮值
                    String nameq = highlightField.getFragments()[0].string();
                    // 覆盖非高亮结果
                    hotelDoc.setName(nameq);
                }
            }

            // 放入集合
            hotels.add(hotelDoc);
        }
        // 4.4.封装返回
        return new PageDTO<ItemDoc> (total, hotels);
    }

}